<template>
  <div>
     <div class="father">
       <div class="box" :class="{active:id === 1}" @click="id = 1">1</div>
       <div class="box" :class="{active:id === 2}" @click="id = 2">2</div>
       <div class="box" :class="{active:id === 3}" @click="id = 3">3</div>
     </div>
   </div>
</template>
 
<script>
export default {

  data() {
    return {
      id:1
    };
  },

  methods: {
  }
};
</script>

<style scoped>
     .box {
        border: 1px solid #333;
        width: 250px;
        height: 250px;
     }

     .father {
       display: flex;
     }

      .active {
        background-color: #087;
     }
</style>